Adult Spinal Deformity
Causes

What are the general types of adult spinal deformity? As we know, the aging process involves segmental (changes between individual sets of vertebrae), regional (cervical, thoracic, lumbar, or sacral), and global (involving the entire spinal column) changes in spinal alignment. Some degree of lost lumbar lordosis or increased thoracic kyphosis may be considered normal with aging. However, when these regional curves no longer compensate well for each other, or when ligamentous and muscular stabilizers fail, then global mal-alignment with significant sagittal plane imbalance may develop (Figure 1). Aging alone, may thus lead to significant sagittal plane deformity. In terms of coronal plane deformity, aging can also contribute to segmental loss of alignment and intervertebral subluxation (usually rotation and displacement laterally, often some degree of spondylolisthesis). This may lead to scoliotic deformity (de-novo degenerative scoliosis, DDS) (Figure 2). The other significant category of coronal plane deformity relates to adults who had some degree of deformity prior to skeletal maturity but may not have been aware of such (most commonly idiopathic scoliosis in the adult, AISA). With aging, deformities of childhood can progress in degree of deformity and lead to marked pain or reduction in activities of daily living (Figure 3).